1. Field of the Invention
This invention is directed to the use of certain specific types of mineral borates, especially calcium or magnesium mineral borates of a generally water-insoluble nature, as flame retardants for organic materials, which borates are employed in a composition containing a source of a halogen of an atomic weight greater than 19. This invention is also directed to imparting to latex foam substances, such as those substances used in carpet backing, increased flame-retardancy by including in the latex foam a water-insoluble mineral borate, such as colemanite or other calcium or magnesium mineral borate. The latex foam contains a source of halide such as chlorine, such as provided by polyvinyl chloride, or a chlorinated, brominated, or iodated organic compound.
2. Discussion of the Prior Art
Borates including some of the mineral borates have been used as fire retardant agents in the past, such as in extinguishing forest fires. Borax and the sodium cation containing materials are generally water-soluble, therefore causing incompatibility problems in some systems.
There is also another major obstacle to their being used in that they are leached out when in contact with a water environment or as in washing or laundering. Hydrated zinc borates are effective fire retardants. However, due to the cost of manufacturing these products, they find application only in specialty products where their high cost is justified. Halogenated materials have also been used as fire retardant agents. Both borates and halogenated materials, when used alone, however, require large amounts of either to be effective.
What has now been discovered is that a composition comprising a relatively crude, inexpensive mineral borate and a halogenated organic material has a synergistic effect in that when only small amounts of each component are employed, significant effective flame retardancy is provided. Such composition, therefore, is an efficient low-cost flame retarding agent.
Numerous fire retardant agents have been proposed for flammable organic materials. Due to current and anticipated Government regulations on items such as carpets there has been an unprecedented desire and demand for effective, economical fire retardants.